1. Field of the Invention
This invention relates to a gas-turbine engine combustor.
2. Description of the Related Art
Since the gas-turbine combustor is suffered from hot combustion gas, Japanese Laid-Open Patent Application No. Hei 10-68523 discloses cooling the combustion chamber liner (inner liner) by combining impingement cooling and film cooling with the use of a perforated liner as the inner liner and a similarly perforated liner faced to the inner liner.
Specifically, in this prior art, the air used as the impingement cooling is also used as the film cooling, and the cooling air is finally introduced in to a combustion section in the combustion chamber where gas under combustion exists. Thus, this prior art proposes improving cooling by combining the impingement cooling and the film cooling.
In the gas-turbine engine combustor, as mentioned in this prior art reference, a part of sucked air is normally used to dilute he combustion gas so as to lower the temperature of combustion gas to a prescribed turbine inlet temperature. However, when this kind of combustor is used for premixed combustion, since premixed combustion is less stable than diffusive combustion, if the diluted air flows back to the combustion section, the stability of combustion could be degraded and the emission of CO could be increased.